I'm not sure that many genres truly die so much as get abandoned in favour of more profitable or higher selling genres.
I mean I doubt everyone who loved platformers or adventure games (as in Monkey Island, Grim Fandango, etc) simply up and died or totally changed their tastes - but I think developers willing to back genres with a smaller potential customer base are far and few between now, while many developers fall over themselves to pander to popular genres to try and cash in.
Just like the movies in fact! I'm still waiting for more intelligent blockbusters, but apparently the modern taste runs to brainless and I'm in the minority - but I digress, blame the horror of taking my kids to Transformers 2.
Try to be reasonable... its easier than you think...
